Optical waveguide structure, optical waveguide display system, vehicle-mounted head-up display device and vehicle

Abstract

The utility model discloses an optical waveguide structure, an optical waveguide display system, a vehicle-mounted head-up display device and a vehicle. The optical waveguide structure comprises an optical transmission medium and a pure reflection grating, and the pure reflection grating is arranged in the optical transmission medium and used for splitting at least part of light in the optical transmission medium into reflected light and transmission light. The pure reflection grating can split the light into the reflection light and the transmission light to be transmitted in the light transmission medium, so that the interval between the coupled light beams can be reduced, and the exit pupil continuity is ensured.

Description

Technical Field

[0001] The present application relates to the field of optical waveguide technology, and in particular to an optical waveguide structure, an optical waveguide display system, a vehicle-mounted head-up display device, and a vehicle. Background Art

[0002] In recent years, optical waveguide display technology for augmented reality and virtual reality has gradually become a key research direction in the display field, and is widely used in the head-up display market, such as head-up displays on cars and aircraft. Among them, the design of the optical waveguide structure is the key to optical waveguide display technology. The current optical waveguide structure couples light into the flat waveguide through a coupling grating for propagation, and then couples the light out through a coupling grating. However, if the propagation angle of light in the flat waveguide is too large or the thickness of the flat waveguide is too large, the light beams are far apart when the light is coupled out, and there will be a problem of discontinuity in the exit pupil. Utility Model Content

[0003] The embodiments of the present application provide an optical waveguide structure, an optical waveguide display system, an in-vehicle head-up display device and a vehicle to solve at least one of the above-mentioned technical problems.

[0004] The optical waveguide structure of the embodiment of the present application includes:

[0005] A light transmission medium and a pure reflection grating, wherein the pure reflection grating is arranged in the light transmission medium and is used to split at least part of the light in the light transmission medium into reflected light and transmitted light.

[0006] In some embodiments, the optical waveguide structure further includes an in-coupling grating and an out-coupling grating, wherein the in-coupling grating is disposed on the surface of the optical transmission medium or in the optical transmission medium, and the out-coupling grating is disposed on the surface of the optical transmission medium or in the optical transmission medium;

[0007] The coupling grating is used to couple light into the optical transmission medium;

[0008] The outcoupling grating is used to couple at least part of the light in the optical transmission medium out of the optical transmission medium.

[0009] In some embodiments, the optical transmission medium comprises two layers, the first layer of the optical transmission medium comprises a first surface and a second surface opposite to each other, the second layer of the optical transmission medium comprises a third surface and a fourth surface opposite to each other, and the second surface is opposite to the third surface;

[0010] The pure reflection grating is arranged between the second surface and the third surface.

[0011] In some embodiments, the coupling-in grating is disposed on the first surface or the fourth surface, or between the second surface and the third surface;

[0012] The outcoupling grating is disposed on the first surface or the fourth surface, or between the second surface and the third surface.

[0013] In some embodiments, the optical waveguide structure includes a photosensitive material layer, and the photosensitive material layer is disposed between the second surface and the third surface;

[0014] The pure reflection grating is formed by exposing a partial area of ​​the photosensitive material layer.

[0015] In some embodiments, the coupling-in grating is disposed between the second surface and the third surface, and the coupling-in grating is formed by exposing a partial area of ​​the photosensitive material layer; and / or,

[0016] The outcoupling grating is arranged between the second surface and the third surface, and the outcoupling grating is formed by exposing a partial area of ​​the photosensitive material layer.

[0017] In certain embodiments, the refractive index of the photosensitive material layer is the same as the refractive index of the light transmitting medium.

[0018] In some embodiments, the length of the photosensitive material layer is the same as the length of the light transmission medium, and / or the width of the photosensitive material layer is the same as the width of the light transmission medium.

[0019] In some embodiments, the coupling-in grating, the pure reflection grating, and the coupling-out grating are sequentially arranged along the extension direction of the optical transmission medium.

[0020] In some embodiments, the fringe periods of the in-coupling grating and the out-coupling grating are consistent.

[0021] In some embodiments, the stripe directions of the coupling-in grating and the coupling-out grating are mirror-symmetrical;

[0022] The number of the pure reflection grating is one, and the pure reflection grating is used to achieve beam expansion of at least part of the light in the optical transmission medium along an extension direction of the optical transmission medium.

[0023] In some embodiments, the pure reflection grating and the coupling-in grating have the same width along the extension direction.

[0024] In some embodiments, the optical waveguide structure further includes a transposed grating, wherein the coupling-in grating, the transposed grating and the coupling-out grating are sequentially arranged along the extension direction of the optical transmission medium, and the transposed grating is used to transform the propagation direction of at least part of the light in the optical transmission medium.

[0025] In some embodiments, the number of the pure reflection gratings is two or more, each of the pure reflection gratings corresponds to one of the extension directions of the optical transmission medium, and each of the pure reflection gratings is used to achieve expansion of at least part of the light in the optical transmission medium along its corresponding extension direction.

[0026] In some embodiments, the pure reflection grating includes a first pure reflection grating and a second pure reflection grating; the coupling-in grating, the first pure reflection grating and the transposed grating are sequentially arranged along a first extension direction of the optical transmission medium, and the transposed grating, the second pure reflection grating and the coupling-out grating are sequentially arranged along a second extension direction of the optical transmission medium;

[0027] The first pure reflection grating is used to realize the expansion of at least part of the light in the optical transmission medium along the first extension direction;

[0028] The transposed grating is used to change the transmission direction of at least part of the light beam expanded by the first pure reflection grating from the first extension direction to the second extension direction;

[0029] The second pure reflection grating is used to achieve beam expansion of at least part of the light after the transmission direction of the transposed grating is transformed along the second extension direction.

[0030] In some embodiments, the width of the first pure reflection grating is the same as that of the coupling grating along the first extension direction; the ratio between the width of the first pure reflection grating along the first extension direction and the width of the second pure reflection grating along the second extension direction is related to the ratio of the light input field of view corresponding to the optical waveguide structure.

[0031] The optical waveguide display system of the embodiment of the present application includes a micro-image source, and the optical waveguide display system also includes the optical waveguide structure of any of the above embodiments, and at least part of the light emitted by the micro-image source is input into the optical waveguide structure.

[0032] The vehicle-mounted head-up display device of the embodiment of the present application includes:

[0033] a housing; and

[0034] In the optical waveguide display system of any of the above embodiments, the optical waveguide display system is disposed in the housing.

[0035] The vehicle of the embodiment of the present application includes a vehicle body; the vehicle also includes an optical waveguide display system of any of the above embodiments or an on-board head-up display device of any of the above embodiments, and the optical waveguide display system or the on-board head-up display device is arranged on the vehicle body.

[0036] In the optical waveguide structure, optical waveguide display system, vehicle-mounted head-up display device and vehicle of the embodiments of the present application, a pure reflection grating is arranged in the optical transmission medium to split at least part of the light in the optical transmission medium into reflected light and transmitted light. Since the pure reflection grating can split the light into reflected light and transmitted light to propagate in the optical transmission medium, the interval between the outcoupled light beams can be reduced, thereby ensuring the continuity of the exit pupil.

[0037] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the technical solutions in the embodiments of the present application or related technologies, the following briefly introduces the drawings required for use in the embodiments or related technical descriptions. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without creative work. Among them:

[0039] Figure 1 is a schematic structural diagram of an optical waveguide display system in some embodiments of the present application;

[0040] Figure 2 is a schematic structural diagram of an optical waveguide structure in some embodiments of the present application;

[0041] Figure 3 is a schematic diagram of the beam expansion principle of a pure reflection grating in certain embodiments of the present application;

[0042] Figure 4 is a schematic structural diagram of an optical waveguide structure in the related art;

[0043] Figure 5 is a schematic diagram of grating distribution of an optical waveguide structure in certain embodiments of the present application;

[0044] Figure 6 is a schematic diagram of grating distribution of an optical waveguide structure in certain embodiments of the present application;

[0045] Figure 7 is a schematic diagram of grating distribution of an optical waveguide structure in certain embodiments of the present application;

[0046] Figure 8is a schematic diagram of grating distribution of an optical waveguide structure in certain embodiments of the present application;

[0047] Fig. 9 is a schematic diagram of the structure of a vehicle head-up display device according to certain embodiments of the present application;

[0048] Fig.10 It is a schematic diagram of the structure of a vehicle of certain embodiments of the present application.

[0049] Description of reference numerals:

[0050] Optical waveguide structure 100, optical transmission medium 10, first layer of optical transmission medium 11, first surface 111, second surface 112, second layer of optical transmission medium 12, third surface 121, fourth surface 122, pure reflection grating 20, first pure reflection grating 21, second pure reflection grating 22, coupling-in grating 30, coupling-out grating 40, photosensitive material layer 50, transposed grating 60, optical waveguide display system 200, micro-image source 210, collimation system 220, vehicle-mounted head-up display device 300, shell 310, body 400, vehicle 1000. DETAILED DESCRIPTION

[0051] The embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals represent the same or similar elements or elements having the same or similar functions from beginning to end. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application, and cannot be understood as limiting the present application.

[0052] See also Figures 1 to 3 The embodiment of the present application provides an optical waveguide structure 100. The optical waveguide structure 100 includes an optical transmission medium 10 and a pure reflection grating 20. The pure reflection grating 20 is disposed in the optical transmission medium 10 to split at least part of the light in the optical transmission medium 10 into reflected light and transmitted light.

[0053] In the optical waveguide structure 100 of the embodiment of the present application, the pure reflection grating 20 is disposed in the optical transmission medium 10, and is used to split at least part of the light in the optical transmission medium 10 into reflected light and transmitted light. Since the pure reflection grating 20 can split the light into reflected light and transmitted light to propagate in the optical transmission medium 10, the interval between the outcoupled light beams can be reduced, thereby ensuring the continuity of the exit pupil.

[0054] Specifically, the optical transmission medium 10 may be a planar waveguide, such as Figure 1 and Figure 2 As shown, the optical transmission medium 10 includes two slab waveguides, and a pure reflection grating 20 is located between the two slab waveguides, so that at least part of the light in the two slab waveguides is split into reflected light and transmitted light.

[0055] See also Figure 3 , when the light is incident on the pure reflection grating 20, the back diffracted light of the incident light coincides with the zero-order reflected light, and the forward diffracted light of the incident light coincides with the zero-order transmitted light. Therefore, after the incident light passes through the pure reflection grating 20, it is split into two beams of light, one reflected light and one transmitted light, thereby achieving beam expansion of the incident light. It should be noted that in the embodiment of the present application, the pure reflection grating 20 is disposed in the optical transmission medium 10 to play a role in expanding the coupled-in light.

[0056] The reflection-transmittance ratio of the pure reflection grating 20 is controlled by the grating thickness and the refractive index modulation. By properly setting the grating thickness and the refractive index modulation, the required reflection-transmittance ratio can be obtained. The incident light angular bandwidth (angular range) that the pure reflection grating 20 can accept depends on the refractive index modulation of the grating. The larger the refractive index modulation, the larger the angular bandwidth. By properly setting the refractive index modulation, semi-transmission and semi-reflection with a certain angular bandwidth can be achieved, and stray light of other orders will not appear. For example, the refractive index modulation of the pure reflection grating 20 can be set to half of the difference between the extreme refractive indices of the light and dark stripes of the grating.

[0057] In the embodiment of the present application, the grating diffraction effect of the pure reflection grating 20 is used for beam splitting, and the light of a certain angular bandwidth can be split into reflected light and transmitted light to propagate in the optical transmission medium 10, so as to achieve beam expansion of light with multiple field of view incident angles. In this way, the interval between the coupled light beams can be reduced, and the continuity of the exit pupil is ensured.

[0058] See also Figure 1 and Figure 2 In some embodiments, the optical waveguide structure 100 further includes an in-coupling grating 30 and an out-coupling grating 40. The in-coupling grating 30 is disposed on the surface of the optical transmission medium 10 or in the optical transmission medium 10. The out-coupling grating 40 is disposed on the surface of the optical transmission medium 10 or in the optical transmission medium 10. The in-coupling grating 30 is used to couple light into the optical transmission medium 10. The out-coupling grating 40 is used to couple at least part of the light in the optical transmission medium 10 out of the optical transmission medium 10.

[0059] Specifically, the coupling-in grating 30 can be disposed on the surface of the optical transmission medium 10 or in the optical transmission medium 10. Figure 1 As shown, the coupling grating 30 is arranged on the surface of the optical transmission medium 10. Figure 2 As shown, the coupling-in grating 30 is disposed in the optical transmission medium 10. The coupling-out grating 40 can be disposed on the surface of the optical transmission medium 10 or in the optical transmission medium 10, such as Figure 1 As shown, the outcoupling grating 40 is arranged on the surface of the optical transmission medium 10. Figure 2 As shown, the outcoupling grating 40 is disposed in the optical transmission medium 10 .

[0060] See also Figure 1 and Figure 2 In the embodiment of the present application, the transmission process of light can be as follows: the micro-image source 210 is set on the focal plane of the collimation system 220 to emit light. The light emitted by each pixel on the micro-image source 210 is converted into parallel light of various azimuth angles by the collimation system 220 as the input light of the coupling grating 30. Due to the diffraction effect of the coupling grating 30, the first-order diffracted light of the input light enters the optical transmission medium 10. In order to be able to propagate losslessly in the optical transmission medium 10, the propagation angle θ of the diffracted light in the optical transmission medium 10 is p The total reflection angle condition of the waveguide must be met, namely:

[0061]

[0062] Where n is the refractive index of the optical transmission medium 10. Since the input light is multi-angle parallel light, the propagation angle of most of the light is greater than The specific value depends on the field of view of the input light. The larger the field of view, the greater the propagation angle θ. p The larger the coupling beam diameter R is, the greater the coupling beam diameter R is. r .

[0063] When the coupled light is transmitted to the pure reflection grating 20, each light beam is split into a reflected light beam and a transmitted light beam after passing through the pure reflection grating 20. The light is then transmitted to the outcoupling grating 40, and after diffraction, its first-order diffraction light no longer meets the total reflection condition, and is emitted from the optical transmission medium 10 into the air. If the first-order diffraction efficiency of the outcoupling grating 40 is not 100%, the zero-order diffraction light continues to propagate in the optical transmission medium 10, thereby coupling out multiple first-order diffraction lights on the outcoupling grating 40. The outcoupling light is multi-angle parallel light corresponding to the coupled light, and the exit pupil diameter is many times the entrance pupil diameter, thereby achieving exit pupil expansion. At this time, the propagation period T of the light determines the exit pupil distance, and the propagation period T depends on the thickness d of the optical transmission medium 10. w The propagation angle θ of the light in the optical transmission medium 10 p ,Right now:

[0064] T=2d w tanθ p

[0065] See also Figure 4 , it is found that when the propagation angle θ p Too large or thick w When it is too large, the propagation period T of the light beam is greater than the beam diameter R. At this time, there will be gaps between the multiple beams of light coupled out by the coupling grating 40, that is, the exit pupil is discontinuous. When applied to the optical waveguide display system 200, the human eye will not be able to see the complete image when moving in the eye box.

[0066] In the optical waveguide structure 100 of the embodiment of the present application, a pure reflection grating 20 is arranged in the optical transmission medium 10, and the coupled light is expanded through the pure reflection grating 20, which is equivalent to increasing the beam diameter R. At this time, In this way, there is no gap between the multiple coupled light beams, which ensures the continuity of the exit pupil of the coupled grating 40 and avoids the situation where the human eye cannot see the complete image when moving in the eye box.

[0067] It should be noted that in the embodiment of the present application, the coupling-in grating 30 and the coupling-out grating 40 may be reflection gratings (such as Figure 1 and Figure 2 ), or a transmission grating. When the coupling-in grating 30 and the coupling-out grating 40 are transmission gratings, Figure 1 The input light can be transmitted to the coupling grating 30 along the negative direction of the Z axis.

[0068] See also Figure 1 and Figure 2 In some embodiments, the optical transmission medium 10 includes two layers. The first layer of the optical transmission medium includes a first surface 111 and a second surface 112 opposite to each other, and the second layer of the optical transmission medium includes a third surface 121 and a fourth surface 122 opposite to each other, and the second surface 112 is opposite to the third surface 121. The pure reflection grating 20 is disposed between the second surface 112 and the third surface 121.

[0069] Specifically, the first layer and the second layer of the optical transmission medium 10 can both be planar waveguides, such as Figure 1 and Figure 2 As shown, the first layer is a first slab waveguide 11, and the second layer is a second slab waveguide 12. The first layer of optical transmission medium can be parallel to the second layer of optical transmission medium. The length of the first layer of optical transmission medium is the same as the length of the second layer of optical transmission medium. The above length is along Figure 1 The width of the first layer of optical transmission medium is the same as the width of the second layer of optical transmission medium. The above width is the size of the first layer of optical transmission medium in the Y-axis direction. Figure 1 The thickness of the first layer of optical transmission medium and the second layer of optical transmission medium can be the same or different, and there is no limitation here. The above thickness is the size of the first layer of optical transmission medium and the second layer of optical transmission medium along the X axis. Figure 1 The first surface 111 and the second surface 112 are respectively the thickness direction of the first layer of optical transmission medium along the optical waveguide structure 100 ( Figure 1 The third surface 121 and the fourth surface 122 are respectively the upper and lower surfaces opposite to each other in the thickness direction of the second layer of optical transmission medium along the optical waveguide structure 100. The pure reflection grating 20 is disposed between the second surface 112 and the third surface 121, and the pure reflection grating 20 can be closely attached to the second surface 112 and the third surface 121.

[0070] See also Figure 1 and Figure 2 In some embodiments, the optical waveguide structure 100 includes a photosensitive material layer 50, and the photosensitive material layer 50 is disposed between the second surface 112 and the third surface 121. The pure reflection grating 20 is formed by exposing a portion of the photosensitive material layer 50.

[0071] Specifically, the photosensitive material layer 50 can be made of photopolymer, silver salt, dichromate, etc. The photosensitive material layer 50 is disposed between the second surface 112 and the third surface 121, and the upper and lower surfaces of the photosensitive material layer 50 along the thickness direction of the optical waveguide structure 100 can be closely attached to the second surface 112 and the third surface 121 respectively.

[0072] In the related art, a semi-transparent corrugated holographic grating or a semi-transparent and semi-reflective film is arranged between two waveguides to achieve beam expansion. Both the semi-transparent corrugated holographic grating and the semi-transparent and semi-reflective film are formed by coating multiple materials on the waveguide surface through a coating process. The coating process is complicated, and each coating process requires the surface of the waveguide to be fully coated, and the environmental requirements are high. In addition, after the coating is completed, it is necessary to sandwich the film again, and the durability of the coating is also required to be high.

[0073] In the embodiment of the present application, the pure reflection grating 20 is a holographic grating with horizontal stripes, and the grating vector is perpendicular to the plane of the slab waveguide ( Figure 1 The pure reflection grating 20 can be formed by holographic exposure of a part of the photosensitive material layer 50, and only the required part of the area needs to be exposed. In addition, after the photosensitive material layer 50 is bonded to the first layer of light transmission medium and the second layer of light transmission medium, a one-time interference exposure operation can be performed by the exposure beam to realize holographic exposure, and the exposure beam is incident in a mirror image with the grating surface. Compared with the coating process, the processing and manufacturing process is relatively simple.

[0074] See also Figure 2 In some embodiments, the coupling-in grating 30 is disposed between the second surface 112 and the third surface 121, and the coupling-in grating 30 is formed by exposing a partial area of ​​the photosensitive material layer 50; and / or the coupling-out grating 40 is disposed between the second surface 112 and the third surface 121, and the coupling-out grating 40 is formed by exposing a partial area of ​​the photosensitive material layer 50.

[0075] Specifically, the coupling-in grating 30 may be disposed between the second surface 112 and the third surface 121, and formed by exposing a portion of the photosensitive material layer 50; in this case, the coupling-out grating 40 may be disposed between the second surface 112 and the third surface 121, or may not be disposed between the second surface 112 and the third surface 121. The coupling-out grating 40 may be disposed between the second surface 112 and the third surface 121, and formed by exposing a portion of the photosensitive material layer 50; in this case, the coupling-in grating 30 may be disposed between the second surface 112 and the third surface 121, or may not be disposed between the second surface 112 and the third surface 121. When both the coupling-in grating 30 and the coupling-out grating 40 are disposed between the second surface 112 and the third surface 121, the coupling-in grating 30, the pure reflection grating 20, and the coupling-out grating 40 are disposed on the same plane between the second surface 112 and the third surface 121, and formed by exposing different regions of the photosensitive material layer 50.

[0076] In some embodiments, the coupling-in grating 30 is disposed on the first surface 111; and / or the coupling-out grating 40 is disposed on the first surface 111. In this case, the coupling-in grating 30 and / or the coupling-out grating 40 are disposed parallel to and spaced from the pure reflection grating 20.

[0077] See also Figure 1 and Figure 2 In some embodiments, the pure reflection grating 20, the coupling-in grating 30 and the coupling-out grating 40 are respectively formed by exposing partial areas of the photosensitive material layer 50.

[0078] Specifically, when the coupling-in grating 30 and the coupling-out grating 40 are disposed together with the pure reflection grating 20 between the second surface 112 and the third surface 121, the pure reflection grating 20, the coupling-in grating 30 and the coupling-out grating 40 can be formed by respectively exposing partial regions of the photosensitive material layer 50. In other words, the coupling-in grating 30, the coupling-out grating 40 and the pure reflection grating 20 can be made of the same material, and the photosensitive material coating is only performed once, and different regions of the photosensitive material layer 50 are respectively exposed to obtain the coupling-in grating 30, the coupling-out grating 40 and the pure reflection grating 20. In this way, the processing and manufacturing process of the optical waveguide structure 100 can be simplified.

[0079] See also Figure 1 and Figure 2 In some embodiments, the refractive index of the photosensitive material layer 50 is the same as the refractive index of the light transmission medium 10 .

[0080] Specifically, the refractive index of the photosensitive material layer 50 is consistent with the refractive index of the optical transmission medium 10. In this way, the Fresnel effect will not occur at the interface between the photosensitive material layer 50 and the first layer of optical transmission medium and the second layer of optical transmission medium, and the unexposed area in the photosensitive material layer 50 will not affect the transmission of light.

[0081] See also Figure 1 and Figure 2 In some embodiments, the length of the photosensitive material layer 50 is the same as the length of the optical transmission medium 10, and / or the width of the photosensitive material layer 50 is the same as the width of the optical transmission medium 10. In this way, the photosensitive material layer 50 and the optical transmission medium can be better bonded, so that the optical waveguide structure 100 has good flatness.

[0082] See also Figure 1 and Figure 2 In some embodiments, the coupling-in grating 30 , the pure reflection grating 20 , and the coupling-out grating 40 are sequentially arranged along the extension direction of the optical transmission medium 10 .

[0083] Specifically, the pure reflection grating 20, the coupling-in grating 30 and the coupling-out grating 40 are projected onto the same plane (eg Figure 1 In the XY plane of FIG. 1 , the coupling-in grating 30, the pure reflection grating 20, and the coupling-out grating 40 are arranged in sequence along the extension direction of the optical transmission medium 10, that is, the pure reflection grating 20 is located between the coupling-in grating 30 and the coupling-out grating 40, so that the light coupled into the coupling-in grating 30 is expanded by the pure reflection grating 20 and then coupled out through the coupling-out grating 40. There is no restriction on the width of the pure reflection grating 20, as long as its projection does not overlap with the projections of the coupling-in grating 30 and the coupling-out grating 40.

[0084] See also Figure 1 , Figure 2 and Figure 5 In some embodiments, the fringe periods of the coupling-in grating 30 and the coupling-out grating 40 are consistent.

[0085] See also Figure 1 , Figure 2 and Figure 5 In some embodiments, the stripe directions of the coupling-in grating 30 and the coupling-out grating 40 are mirror-symmetrical.

[0086] Specifically, the coupling-in grating 30 is used to couple the input light into the optical transmission medium 10 and transmit it, and the coupling-out grating 40 is used to couple out the light transmitted in the two optical transmission media 10. When the stripe periods of the coupling-in grating 30 and the coupling-out grating 40 are consistent, the coupling-in grating 30 and the coupling-out grating 40 are in the same period. Figure 1 The sum of the grating vectors on the XY plane is zero, and the light coupled out through the coupling grating 40 is consistent with the input light, and the light will not be dispersed. The coupling grating 30 and the coupling grating 40 have opposite effects, so the stripe directions of the two are mirror-symmetric.

[0087] See also Figure 1 , Figure 2 and Figure 5In some embodiments, the number of the pure reflection grating 20 is one. The pure reflection grating 20 is used to achieve beam expansion of at least part of the light in the optical transmission medium 10 along an extension direction of the optical transmission medium 10.

[0088] like Figure 5 As shown, Figure 5 for Figure 2 In the cross-sectional view along line VV, there is one pure reflection grating 20. At least part of the light coupled into the optical transmission medium 10 is expanded along an extension direction of the optical transmission medium 10 at the pure reflection grating 20, so that the optical waveguide structure 100 can achieve one-dimensional pupil expansion.

[0089] See also Figure 1 , Figure 2 and Figure 5 In some embodiments, the pure reflection grating 20 and the coupling-in grating 30 have the same width along the extension direction.

[0090] Specifically, the width of the pure reflection grating 20 along the extension direction is the same as the width of the coupling grating 30 along the extension direction, so that the pure reflection grating 20 can better receive the light coupled in by the coupling grating 30 for beam expansion. Figure 1 and Figure 5 The middle Y axis direction.

[0091] See also Figure 1 , Figure 2 and Figure 5 In some embodiments, the length of the coupling-in grating 30 perpendicular to the extension direction is greater than the length of the pure reflection grating 20 perpendicular to the extension direction, and the length of the pure reflection grating 20 perpendicular to the extension direction is greater than the length of the coupling-out grating 40 perpendicular to the extension direction. Figure 5 The length of the center along the X-axis direction. In this way, the edge of the exit pupil is ensured to be clearly displayed.

[0092] See also Figures 6 to 8 In some embodiments, the optical waveguide structure 100 further includes a transposed grating 60. The in-coupling grating 30, the transposed grating 60, and the out-coupling grating 40 are sequentially arranged along the extension direction of the optical transmission medium 10, and the transposed grating 60 is used to transform the propagation direction of at least part of the light in the optical transmission medium 10.

[0093] The transposed grating 60 can also be formed by exposing a part of the photosensitive material layer 50. The specific exposure formation process is similar to that of the pure reflection grating 20, the coupling-in grating 30 and the coupling-out grating 40, and will not be described in detail here.

[0094] by Figure 6For example, the transmission process of light can be as follows: the input light is coupled into the optical transmission medium 10 through the coupling grating 30 and transmitted. When the coupled light is transmitted to the pure reflection grating 20, it is split into a beam of reflected light and a beam of transmitted light by the pure reflection grating 20. The light after beam expansion continues to be transmitted to the transposed grating 60, and at least part of the light continues to be transmitted to the coupling grating 40 after changing direction, part of the light is coupled out, and part of the light continues to be transmitted, and finally multiple beams of light after beam expansion can be coupled out to achieve one-dimensional pupil expansion.

[0095] See also Figure 7 and Figure 8 In some embodiments, the number of pure reflection gratings 20 is two or more, each pure reflection grating 20 corresponds to one of the extension directions of the optical transmission medium 10, and each pure reflection grating 20 is used to achieve the expansion of at least part of the light in the optical transmission medium 10 along its corresponding extension direction.

[0096] Specifically, the number of pure reflection gratings 20 may be two, or any number greater than two, for example, the number of pure reflection gratings 20 may be three, four or more. Each pure reflection grating 20 corresponds to one of the extension directions of the optical transmission medium 10. For example, the number of pure reflection gratings 20 is two. Figure 7 and Figure 8 As shown, a pure reflection grating 20 corresponds to the length extension direction of the optical transmission medium 10, and can realize the expansion of at least part of the light in the optical transmission medium 10 along the length extension direction of the optical transmission medium 10; a pure reflection grating 20 corresponds to the width extension direction of the optical transmission medium 10, and can realize the expansion of at least part of the light in the optical transmission medium 10 along the width extension direction of the optical transmission medium 10.

[0097] See also Figure 7 and Figure 8 In some embodiments, the pure reflection grating 20 includes a first pure reflection grating 21 and a second pure reflection grating 22. The coupling-in grating 30, the first pure reflection grating 21 and the transposed grating 60 are sequentially arranged along the first extension direction of the optical transmission medium 10, and the transposed grating 60, the second pure reflection grating 22 and the coupling-out grating 40 are sequentially arranged along the second extension direction of the optical transmission medium 10. The first pure reflection grating 21 is used to realize the expansion of at least part of the light in the optical transmission medium 10 along the first extension direction. The transposed grating 60 is used to change the transmission direction of at least part of the light expanded by the first pure reflection grating 21 from the first extension direction to the second extension direction. The second pure reflection grating 22 is used to realize the expansion of at least part of the light after the transposed grating 60 changes the transmission direction along the second extension direction.

[0098] Specifically, Figure 7 As shown, the projection of the first pure reflection grating 21 on the optical transmission medium 10 is a trapezoid, as shown in FIG. Figure 7 As shown, the projection of the first pure reflection grating 21 on the optical transmission medium 10 is a rectangle. Of course, the first pure reflection grating 21 can be set to any other shape, so that the projection of the first pure reflection grating 21 on the optical transmission medium 10 can also be any other shape, which is not limited here. The size of the first pure reflection grating 21 depends on the field of view of the coupled light. When the projection of the first pure reflection grating 21 on the optical transmission medium 10 is a trapezoid, the larger the field of view, the smaller the bottom angle of the trapezoid, so that the first pure reflection grating 21 can better receive the light coupled in through the coupling grating 30 for beam expansion. The projection of the second pure reflection grating 22 on the optical transmission medium 10 is a rectangle. Of course, the first pure reflection grating 21 can be set to any shape, and the projection of the first pure reflection grating 21 on the optical transmission medium 10 can also be any shape, which is not limited here.

[0099] like Figure 7 and Figure 8 As shown, the first extension direction of the optical transmission medium 10 can be the X-axis direction, and the coupling-in grating 30, the first pure reflection grating 21 and the transposed grating 60 are sequentially arranged along the X-axis direction. The first pure reflection grating 21 can realize the expansion of at least part of the light in the optical transmission medium 10 along the X-axis direction. The second extension direction of the optical transmission medium 10 can be the Y-axis direction, and the transposed grating 60, the second pure reflection grating 22 and the coupling-out grating 40 are sequentially arranged along the second extension direction of the optical transmission medium 10. The transposed grating 60 can change the transmission direction of at least part of the light expanded by the first pure reflection grating 21 from the X-axis direction to the Y-axis direction. The second pure reflection grating 22 can realize the expansion of at least part of the light after the transposed grating 60 changes the transmission direction along the Y-axis direction.

[0100] In the implementation manner of the present application, the transmission process of light can be as follows: the input light is coupled into the optical transmission medium 10 through the coupling-in grating 30 and transmitted. When the coupled-in light is transmitted to the first pure reflection grating 21, it is split into a beam of reflected light and a beam of transmitted light in the first direction by the first pure reflection grating 21, thereby realizing the first beam expansion. The light after the first beam expansion continues to be transmitted to the transposed grating 60, and continues to be transmitted after changing direction. When the light is transmitted to the second pure reflection grating 22, it is split into a beam of reflected light and a beam of transmitted light in the second direction by the second pure reflection grating 22, thereby realizing the second beam expansion. It can be understood that the first direction is different from the second direction. Afterwards, when the light is transmitted to the coupling-out grating 40, part of the light is coupled out, and part of the light continues to be transmitted, and finally multiple beams of light that have been expanded in two directions can be coupled out to realize two-dimensional pupil expansion.

[0101] See also Figure 7 and Figure 8In some embodiments, the first pure reflection grating 21 has the same width as the coupling grating 30 along the first extension direction. The ratio between the width of the first pure reflection grating 21 along the first extension direction and the width of the second pure reflection grating 22 along the second extension direction is related to the ratio of the light input field of view corresponding to the optical waveguide structure.

[0102] Specifically, the first pure reflection grating 21 and the coupling-in grating 30 are connected along the first extension direction (eg Figure 7 and Figure 8 In this way, the first pure reflection grating 21 can better receive the light coupled in by the coupling grating 30. Figure 8 As shown, the width of the first pure reflection grating 21 along the first extension direction is L1, and the width of the second pure reflection grating 22 along the second extension direction is L2. The ratio between L1 and L2 is related to the light input field of view ratio corresponding to the optical waveguide structure. The light input field of view ratio corresponding to the optical waveguide structure is FOV(H):FOV(V), where FOV(H) is the horizontal field of view (field of view width) and FOV(V) is the vertical field of view (field of view length). Then the ratio between L1 and L2 is:

[0103] L1:L2=FOV(H):FOV(V)

[0104] In some embodiments, the length of the second pure reflection grating 22 perpendicular to the second extension direction is the same as the length of the outcoupling grating 40 perpendicular to the second extension direction, so that the outcoupling grating 40 can better receive and outcouple the light after being expanded by the second pure reflection grating 22.

[0105] See also Figure 1 The present application also provides a light waveguide display system 200 . The light waveguide display system 200 includes a micro image source 210 , and the light waveguide display system 200 also includes a light waveguide structure 100 as described in any of the above embodiments. At least part of the light emitted by the micro image source 210 is input into the light waveguide structure 100 .

[0106] Specifically, the optical waveguide display system 200 further includes a collimation system 220, and the light emitted by the micro-image source 210 is at least partially input into the optical waveguide structure 100 through the collimation system 220. The optical waveguide display system 200 can be applied to a head-up display (HUD), such as a vehicle-mounted head-up display device 300 or a head-up display device on an airplane.

[0107] See also Fig. 9 The embodiment of the present application also provides a vehicle-mounted head-up display device 300, including a housing 310 and an optical waveguide display system 200 of any of the above-mentioned embodiments, and the optical waveguide display system 200 is disposed in the housing 310.

[0108] See also Fig.10 The embodiment of the present application also provides a vehicle 1000, including a vehicle body 400, the vehicle 1000 also includes an optical waveguide display system 200 of any of the above embodiments or an in-vehicle head-up display device 300 of any of the above embodiments, and the optical waveguide display system 200 or the in-vehicle head-up display device 300 is arranged on the vehicle body 400.

[0109] Specifically, the vehicle 1000 may include any one of the optical waveguide display system 200 and the vehicle-mounted head-up display device 300. Taking the vehicle 1000 including the vehicle-mounted head-up display device 300 as an example, the vehicle-mounted head-up display device 300 may be arranged at the front of the vehicle body 400. When the user is driving the vehicle 1000, the vehicle-mounted head-up display device 300 may form a virtual image of information such as vehicle speed and navigation in front of the user's line of sight, so that the user can conveniently view the vehicle 1000 information without lowering his head, which is conducive to safe driving.

[0110] In summary, in the optical waveguide structure 100, the optical waveguide display system 200, the vehicle-mounted head-up display device 300 and the vehicle 1000 of the embodiment of the present application, the pure reflection grating 20 is disposed in the optical transmission medium 10, and is used to split at least part of the light in the optical transmission medium 10 into reflected light and transmitted light. Since the pure reflection grating 20 can split the light into reflected light and transmitted light to propagate in the optical transmission medium 10, the interval between the outcoupled light beams can be reduced, thereby ensuring the continuity of the exit pupil.

[0111] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first" and "second" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more features. In the description of the present application, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.

[0112] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0113] In the present application, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0114] The disclosure above provides many different embodiments or examples to realize the different structures of the present application. In order to simplify the disclosure of the present application, the parts and settings of specific examples are described above. Of course, they are only examples, and the purpose is not to limit the present application. In addition, the present application can repeat reference numbers and / or reference letters in different examples, and this repetition is for the purpose of simplification and clarity, which itself does not indicate the relationship between the various embodiments and / or settings discussed. In addition, the present application provides various specific processes and examples of materials, but those of ordinary skill in the art can appreciate the application of other processes and / or the use of other materials.

[0115] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "example", "specific example", "some examples", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiments or examples are included in at least one embodiment or example of the present application. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0116] Although the embodiments of the present application have been shown and described above, those skilled in the art will appreciate that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present application, and that the scope of the present application is defined by the claims and their equivalents.

Claims

1. An optical waveguide structure (100), characterized in that: include: An optical transmission medium (10) and a pure reflection grating (20), wherein the pure reflection grating (20) is arranged in the optical transmission medium (10) and is used to split at least part of the light in the optical transmission medium (10) into reflected light and transmitted light.

2. The optical waveguide structure (100) according to claim 1, characterized in that: The optical waveguide structure (100) further comprises an in-coupling grating (30) and an out-coupling grating (40), wherein the in-coupling grating (30) is arranged on the surface of the optical transmission medium (10) or in the optical transmission medium (10), and the out-coupling grating (40) is arranged on the surface of the optical transmission medium (10) or in the optical transmission medium (10); The coupling grating (30) is used to couple light into the optical transmission medium (10); The outcoupling grating (40) is used to couple at least part of the light in the optical transmission medium (10) out of the optical transmission medium (10).

3. The optical waveguide structure (100) according to claim 2, characterized in that: The optical transmission medium (10) comprises two layers, the first layer of the optical transmission medium (10) comprises a first surface (111) and a second surface (112) opposite to each other, the second layer of the optical transmission medium (10) comprises a third surface (121) and a fourth surface (122) opposite to each other, and the second surface (112) is opposite to the third surface (121); The pure reflection grating (20) is arranged between the second surface (112) and the third surface (121).

4. The optical waveguide structure (100) according to claim 3, characterized in that: The coupling-in grating (30) is arranged on the first surface (111) or the fourth surface (122), or between the second surface (112) and the third surface (121); The outcoupling grating (40) is arranged on the first surface (111) or the fourth surface (122), or between the second surface (112) and the third surface (121).

5. The optical waveguide structure (100) according to claim 3, characterized in that: The optical waveguide structure (100) comprises a photosensitive material layer (50), wherein the photosensitive material layer (50) is arranged between the second surface (112) and the third surface (121); The pure reflection grating (20) is formed by exposing a partial area of ​​the photosensitive material layer (50).

6. The optical waveguide structure (100) according to claim 5, characterized in that: The coupling-in grating (30) is arranged between the second surface (112) and the third surface (121), and the coupling-in grating (30) is formed by exposing a partial area of ​​the photosensitive material layer (50); and / or, The outcoupling grating (40) is arranged between the second surface (112) and the third surface (121), and the outcoupling grating (40) is formed by exposing a partial area of ​​the photosensitive material layer (50).

7. The optical waveguide structure (100) according to claim 5, characterized in that: The refractive index of the photosensitive material layer (50) is the same as the refractive index of the optical transmission medium (10).

8. The optical waveguide structure (100) according to any one of claims 5 to 7, characterized in that: The length of the photosensitive material layer (50) is the same as the length of the optical transmission medium (10), and / or the width of the photosensitive material layer (50) is the same as the width of the optical transmission medium (10).

9. The optical waveguide structure (100) according to claim 2, characterized in that: The coupling-in grating (30), the pure reflection grating (20), and the coupling-out grating (40) are arranged in sequence along the extension direction of the optical transmission medium (10).

10. The optical waveguide structure (100) according to claim 9, characterized in that: The stripe periods of the coupling-in grating (30) and the coupling-out grating (40) are consistent.

11. The optical waveguide structure (100) according to claim 9 or 10, characterized in that: The stripe directions of the coupling-in grating (30) and the coupling-out grating (40) are mirror-symmetrical; The number of the pure reflection grating (20) is one, and the pure reflection grating (20) is used to achieve beam expansion of at least part of the light in the optical transmission medium (10) along an extension direction of the optical transmission medium (10).

12. The optical waveguide structure (100) according to claim 11, characterized in that: The pure reflection grating (20) and the coupling-in grating (30) have the same width along the extension direction.

13. The optical waveguide structure (100) according to claim 9 or 10, characterized in that: The optical waveguide structure (100) further comprises a transposed grating (60), wherein the coupling-in grating (30), the transposed grating (60) and the coupling-out grating (40) are arranged in sequence along the extension direction of the optical transmission medium (10), and the transposed grating (60) is used to transform the propagation direction of at least part of the light in the optical transmission medium (10).

14. The optical waveguide structure (100) according to claim 13, characterized in that: The number of the pure reflection gratings (20) is two or more, each of the pure reflection gratings (20) corresponds to one of the extension directions of the optical transmission medium (10), and each of the pure reflection gratings (20) is used to achieve beam expansion of at least part of the light in the optical transmission medium (10) along its corresponding extension direction.

15. The optical waveguide structure (100) according to claim 14, characterized in that: The pure reflection grating (20) comprises a first pure reflection grating (21) and a second pure reflection grating (22); the coupling-in grating (30), the first pure reflection grating (21) and the transposed grating (60) are arranged in sequence along a first extension direction of the optical transmission medium (10); and the transposed grating (60), the second pure reflection grating (22) and the coupling-out grating (40) are arranged in sequence along a second extension direction of the optical transmission medium (10); The first pure reflection grating (21) is used to achieve beam expansion of at least part of the light in the optical transmission medium (10) along the first extension direction; The transposed grating (60) is used to change the transmission direction of at least part of the light beam expanded by the first pure reflection grating (21) from the first extension direction to the second extension direction; The second pure reflection grating (22) is used to achieve beam expansion along the second extension direction of at least part of the light after the transmission direction of the transposed grating (60) is transformed.

16. The optical waveguide structure (100) according to claim 15, characterized in that: The first pure reflection grating (21) and the coupling grating (30) have the same width along the first extension direction; the ratio between the width of the first pure reflection grating (21) along the first extension direction and the width of the second pure reflection grating (22) along the second extension direction is related to the ratio of the light input field of view corresponding to the optical waveguide structure (100).

17. An optical waveguide display system (200), characterized in that: The optical waveguide display system (200) comprises a micro-image source, and further comprises an optical waveguide structure (100) as claimed in any one of claims 1 to 16, wherein at least part of the light emitted by the micro-image source is input into the optical waveguide structure (100).

18. A vehicle-mounted head-up display device (300), characterized in that: include: Housing (310); and The light guide display system (200) of claim 17, wherein the light guide display system (200) is disposed in the housing (310).

19. A vehicle (1000), characterized in that: The vehicle (1000) comprises a vehicle body (400); the vehicle (1000) further comprises the optical waveguide display system (200) as claimed in claim 17 or the vehicle-mounted head-up display device (300) as claimed in claim 18, and the optical waveguide display system (200) or the vehicle-mounted head-up display device (300) is arranged on the vehicle body (400).

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